Sucrose is implicated in the development of obesity and cardiovascular disease, because high intakes of fructose are known to lead to insulin resistance, metabolic syndrome and diabetes. In recent decades, fructose consumption has increased in Western nations, particularly through an increase in sweetened drink consumption. There is good evidence that this increase in fructose has been largely damaging to the health of Western populations with research showing that consumption of 2 sugar sweetened drink per day increases the risk of cardiovascular disease by ≈35%, compared to consumption of less than 1 drink. The reason that fructose may be so damaging is because it increase rates of de novo lipogenesis in the liver and this in turn increases levels of very low density lipoprotein (VLDL). The saturated fatty acids may then accumulate in intramyocellular spaces and interfere with signal molecules, ultimately decreasing peripheral insulin sensitivity.
Researchers1 have investigated the effects of sugar sweetened drinks on the glucose and lipid metabolism of 29 normal-weight subjects. Subjects were assigned to receive various sweetened drinks in 3 week interventions. The 600mL drinks contained either 40g fructose, 80g fructose, 40g glucose, 80g glucose, or 80g sucrose. Consumption of the 80g fructose drink for 3 weeks resulted in a significant decrease in the low density lipoprotein (LDL) particle size. In addition, both fructose drinks and the sucrose drink significantly decreased the plasma levels of the large buoyant LDL I subclass which created a more pro-atherogenic lipid profile. However, there was no change in the traditional LDL, high density lipoprotein (HDL) or total cholesterol lipid parameters. After all drinks the fasting glucose levels also increased suggesting that insulin sensitivity had decreased and increased C-reactive protein reflected increased systemic inflammation.
Increased quantities of small dense LDL particles (pattern B) is a known risk factor for cardiovascular disease. This study shows that 3 weeks of consuming 600mL fructose sweetened drinks causes detrimental changes to the LDL particle size that could increase the risk of cardiovascular disease. However, the lack of change to the ratio of LDL, HDL and total cholesterol suggest that the changes in lipoproteins are subtle. The authors suggested that a longer study may be needed to see changes in traditional values. The subjects consuming the fructose and sucrose drinks experienced an increase in the waist-to-hip ratio which is also indicative of an increase in the risk of developing cardiovascular disease. Interestingly, leptin level only increased with consumption of the glucose sweetened drink, and this may imply that fructose in some way prevents rises in serum leptin levels and may therefore bypass normal appetite regulation.
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